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United States Patent |
5,546,965
|
White
|
August 20, 1996
|
Cigarette with improved fuel element insulator
Abstract
The present invention provides improved cigarettes and other smoking
articles employing short fuel elements and physically separate aerosol
generating means wherein the fuel element is provided with an improved
insulating means comprising extremely fine gauge (e.g., about 0.002 inch
diameter) wire, woven into a cloth-like material of about 200 mesh.
Inventors:
|
White; Jackie L. (Pfafftown, NC)
|
Assignee:
|
R. J. Reynolds Tobacco Company (Winston-Salem, NC)
|
Appl. No.:
|
263626 |
Filed:
|
June 22, 1994 |
Current U.S. Class: |
131/194 |
Intern'l Class: |
A24F 047/00; A24D 001/00 |
Field of Search: |
131/194
|
References Cited
U.S. Patent Documents
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| |
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| |
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| |
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| |
4782644 | Nov., 1988 | Haarer et al.
| |
4793365 | Dec., 1988 | Sensabaugh, Jr. et al.
| |
4802568 | Feb., 1989 | Haarer et al.
| |
4819665 | Apr., 1989 | Roberts et al.
| |
4827950 | May., 1989 | Banerjee et al.
| |
4854331 | Aug., 1989 | Banerjee et al.
| |
4858630 | Aug., 1989 | Banerjee et al.
| |
4881556 | Nov., 1989 | Clearman et al.
| |
4893637 | Jan., 1990 | Hancock et al.
| |
4893639 | Jan., 1990 | White.
| |
4903714 | Feb., 1990 | Barnes et al.
| |
4917128 | Apr., 1990 | Clearman et al.
| |
4928714 | May., 1990 | Shannon.
| |
4938238 | Jul., 1990 | Barnes et al.
| |
4966171 | Oct., 1990 | Serrano et al.
| |
4967774 | Nov., 1990 | White.
| |
4981522 | Jan., 1991 | Nichols et al.
| |
4989619 | Feb., 1991 | Clearman et al.
| |
4991606 | Feb., 1991 | Serrano et al.
| |
5019122 | May., 1991 | Clearman et al.
| |
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| |
5027836 | Jul., 1991 | Shannon et al.
| |
5027837 | Jul., 1991 | Clearman et al.
| |
5033483 | Jul., 1991 | Clearman et al.
| |
5042509 | Aug., 1991 | Banerjee et al.
| |
5052413 | Oct., 1991 | Baker et al.
| |
5060666 | Oct., 1991 | Clearman et al.
| |
5065776 | Nov., 1991 | Lawson et al.
| |
5067499 | Nov., 1991 | Banerjee et al.
| |
5076292 | Dec., 1991 | Sensabaugh, Jr. et al.
| |
5076296 | Dec., 1991 | Nystrom et al.
| |
5076297 | Dec., 1991 | Farrier et al.
| |
5088507 | Feb., 1992 | Baker et al.
| |
5099861 | Mar., 1992 | Clearman et al.
| |
5105831 | Apr., 1992 | Banerjee et al.
| |
5105837 | Apr., 1992 | Barnes et al.
| |
5119834 | Jun., 1992 | Shannon et al.
| |
5119837 | Jun., 1992 | Banerjee et al.
| |
5129409 | Jul., 1992 | White et al.
| |
5133368 | Jul., 1992 | Neumann et al.
| |
5137034 | Aug., 1992 | Perfetti et al.
| |
5146934 | Sep., 1992 | Deevi et al.
| |
5156170 | Oct., 1992 | Clearman et al.
| |
5159940 | Nov., 1992 | Hayward et al.
| |
5178167 | Jan., 1993 | Riggs et al.
| |
5183062 | Feb., 1993 | Clearman et al.
| |
5188130 | Feb., 1993 | Hajaligol et al.
| |
5203355 | Apr., 1993 | Clearman et al.
| |
5211684 | May., 1993 | Shannon et al.
| |
5240016 | Aug., 1993 | Nichols et al.
| |
5247947 | Sep., 1993 | Clearman et al.
| |
5303720 | Apr., 1994 | Banerjee et al.
| |
Other References
U.S. Serial No. 07/800,679 - filed Jan. 2, 1991.
U.S. Serial No. 07/882,209 - Filed May 13, 1992.
Tobacco Flavoring For Smoking Products, RJR (1972).
|
Primary Examiner: Bahr; Jennifer
Claims
What is claimed is:
1. A smoking article comprising:
(a) a combustible fuel element less than about 30 mm in length prior to
smoking, said fuel element being insulated by an insulating material
surrounding at least a portion of the periphery thereof; and
(b) a physically separate aerosol generating means disposed longitudinally
behind the fuel element comprising a substrate material bearing an aerosol
forming material;
wherein the insulating material for the fuel element comprises a wire cloth
or a noncombustible synthetic cloth material.
2. The smoking article of claim 1, wherein the wire cloth insulating
material comprises a metal.
3. The smoking article of claim 2, wherein the metal wire is aluminum.
4. The smoking article of claim 1, wherein the noncombustible synthetic
insulating material comprises a high temperature stable synthetic
material.
5. The smoking article of claim 1, wherein the wire cloth insulating
material comprises several resilient layers, providing a thickness of
insulating material of from about 0.5 to about 3 mm around the periphery
of the fuel element.
6. The smoking article of claim 5, wherein the thickness of the resilient
wire cloth insulating material is from about 1 to 2.5 mm.
7. The smoking article of claim 5, wherein the thickness of the resilient
wire cloth insulating material is from about 1.5 to about 2 mm.
8. The smoking article of any of claims 1-7, wherein the wired cloth
insulating material is woven into a pattern selected from the group
consisting of Plain Square Weave, Twilled Square Weave, Plain Dutch Weave,
Twilled Dutch Weave, Robusta Reverse Dutch Weave, Braided Weave and Basket
Weave.
9. The smoking article of any of claims 1-7, wherein the mesh count ranges
from about 50 to 400.
10. The smoking article of any of claims 1-7, wherein the mesh count ranges
from about 100 to 300.
11. The smoking article of any of claims 1-7, wherein the diameter of the
wire ranges from about 0.0008 inches to about 0.063 inches.
12. The smoking article of any of claims 1-7, wherein the diameter of the
wire ranges from about 0.0005 inches to about 0.005 inches.
13. The smoking article of any of claims 1-7, wherein the diameter of the
wire ranges from about 0.001 inches to about 0.003 inches.
14. The smoking article of any of claims 1-7, wherein the open area of the
wire cloth insulator ranges from about 20% to about 80%.
15. The smoking article of claim 14, wherein the open area of the wire
cloth insulator ranges from about 30% to about 70%.
16. The smoking article of claim 14, wherein the open area of the wire
cloth insulator ranges from about 40% to about 60%.
17. The smoking article of any of claims 1-7, wherein the wire cloth
insulator has been texturized or corrugated to modify the open area or
degree of insulating power thereof.
18. The smoking article of claim 1, wherein the wire cloth insulator
comprises an aluminum wire cloth, having a plain square weave.
19. The smoking article of claim 18, wherein the wire cloth insulator has a
mesh count of 200 and a wire diameter of 0.0021 inches, providing an open
area of 33.6%.
Description
BACKGROUND OF THE INVENTION
The present invention relates to smoking articles such as cigarettes, and
in particular, to those smoking articles having a short fuel element and a
physically separate aerosol generating means. These smoking articles are
capable of providing the smoker with the pleasures of smoking (e.g.,
smoking taste, feel, satisfaction, and the like). The following U.S. Pat.
Nos. are directed to such articles; 4,714,082; 4,732,168; 4,756,318;
4,771,795; 4,782,644; 4,793,365; 4,802,568; 4,819,665; 4,827,950;
4,854,331; 4,858,630; 4,881,556; 4,989,619; 4,893,637; 4,893,639;
4,903,714; 4,917,128; 4,928,714; 4,938,238; 4,966,171; 4,967,774;
4,981,522; 4,989,619; 4,991,606; 5,019,122; 5,020,548; 5,027,836;
5,027,837; 5,033,483; 5,042,509; 5,052,413; 5,060,666; 5,065,776;
5,067,499; 5,076,292; 5,076,296; 5,076,297; 5,088,507; 5,099,861;
5,105,831; 5,105,837; 5,119,834; 5,119,837; 5,129,409; 5,133,368;
5,137,034; 5,146,934; 5,156,170; 5,159,940; 5,178,167; 5,183,062;
5,188,130; 5,203,355; 5,211,684; 5,240,016; 5,247,947; and 5,303,720, and
their disclosures are hereby incorporated herein by reference.
Many of the smoking articles described in the above cited prior art employ
a combustible fuel element for heat generation and an aerosol generating
means positioned physically separate from, and in a heat exchange
relationship with, the fuel element. The aerosol generating means
typically includes one or more aerosol forming substances such as glycerin
in or on a substrate or carrier. These smoking articles also normally
include tobacco in various forms such as cut filler, reconstituted
tobaccos, densified pellets, tobacco dust and tobacco extracts, as well as
tobacco flavor modifiers and tobacco flavoring agents. During smoking,
heat generated by the fuel element acts to volatilize the aerosol forming
substances, thereby providing an aerosol which resembles tobacco smoke.
Such smoking articles yield extremely low levels of visible sidestream
smoke as well as low levels of FTC "tar."
Many of the smoking articles described above employ an insulated fuel
element and some use an insulating material such as nonrespirable glass
fibers. See, e.g., U.S. Pat. Nos. 5,027,836, and 5,303,720. One common
example of such glass fibers is Owen-Corning C-glass, the fibers of which
have an average diameter of about 8 .mu.m. Other types of insulating
material sometimes include tobacco, tobacco paper, alumina, mineral wool,
carbon, organic polymers, pearlite glass, calcium sulfate fibers, and/or
calcium or sodium phosphate fibers. The present invention represents an
alternative to the previously employed insulating materials.
SUMMARY OF THE INVENTION
The present invention provides an improved insulating means for cigarettes
and other smoking articles employing short fuel elements and physically
separate aerosol generating means. The improved insulating means comprises
a woven wire cloth material. Preferably, the wire is extremely fine gauge
(e.g., about 0.002 inches in diameter) wire, and is woven in a fine mesh
form (e.g., 200 mesh) and is made of a metal (e.g., aluminum).
It has surprisingly been discovered that wire cloth as described above is
particularly well suited for use as an insulating means around the
preferred short carbon fuel in the cigarettes of the present invention.
Being a metal (or noncombustible synthetic) wire, it is chemically inert
and non-burnable under the conditions typically encountered during
smoking. The wire cloth insulating material of the present invention is
both non-fibrous and inorganic, and thus contributes neither off-tastes
nor foreign materials to the mainstream aerosol.
The wire cloth insulating material is normally formed around the fuel
element in multilayers to provide an insulating jacket having a thickness
of from about 0.5 mm to about 3.0 mm, preferably about 1.0 to about 2.5
mm, and most preferably about 1.5 to about 2.0 mm. Such a jacket is
resilient to the touch. The mesh opening in the wire cloth material
provides a porous layer which performs as a good insulating material, but
also allows sufficient oxygen through the periphery to sustain combustion
of the fuel element as required.
In one preferred embodiment, the wire cloth insulating material consists of
extremely fine gauge (0.002 inch) aluminum wire, woven into a cloth like
material of about 200 mesh. A piece of this material (about 12
mm.times.120 mm) and weighing about 0.15 g is rolled around a 12 mm fuel
element. The wire cloth insulating material is very porous and
multi-layered. Because of the nature of the wire cloth material, when
wrapped or rolled around itself, it forms a good fuel element insulator.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a longitudinal sectional view of a cigarette of the present
invention.
FIG. 1A is a front end view of the cigarette illustrated in FIG. 1.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
The cigarette illustrated in FIGS. 1 and 1A, has a fuel element 10, which
includes a number of grooves 15 running along its longitudinal periphery.
As shown, the improved wire cloth insulating jacket of the present
invention 12 surrounds the periphery of the fuel element. An outer paper
wrapper 14 may comprise one layer or may be prepared from a plurality of
separate layers, each having different porosity and ash stability
characteristics.
The aerosol generating means, which includes substrate 16 contains one or
more aerosol forming materials and/or flavorants is situated behind the
insulated fuel element 10. The substrate material 16 may be any one of a
number of materials, including reconstituted tobacco or tobacco paper,
wood paper, heat-stabilized paper, e.g., paper treated with one or more
hydrated salts; tobacco paper and the like. See U.S. Pat. Nos. 5,183,062,
5,203,335 and U.S. patent application Nos. 07/800,679, filed Nov. 2, 1991
and 07/882,209, filed May 13, 1992.
The aerosol generating means also includes at least one aerosol forming
material, on or in the substrate. The aerosol forming material generally
has a liquid form. Examples of preferred aerosol forming materials include
the polyhydric alcohols (e.g., glycerin, propylene glycol and triethylene
glycol), the aliphatic esters of mono-, di-, or poly-carboxylic acids
(e.g., methyl stearate, dimethyl dodecandioate and dimethyl
tetradecanedioate), and the like.
Substrate 16 is overwrapped with an overwrap 17 which may include a barrier
material to reduce or preferably prevent any migration of the aerosol
forming materials from the substrate to other parts of the cigarette.
Preferably, the overwrap comprises a laminated foil/paper combination.
Spaced longitudinally behind the substrate 16 is a segment of reconstituted
tobacco 19, overwrapped with paper 20. This tobacco segment is used to
provide tobacco flavors to the aerosol emitted from the aerosol generating
means.
Positioned at the extreme mouth end of the cigarette is a low-efficiency
filter element 21, overwrapped with paper 22. Standard paper overwrap 24
combines the tobacco section 19 and the filter 21.
Circumscribing the insulated fuel element, at a point about 2 to 8 mm from
the lighting end of the cigarette, and combining it with barrier wrapper
17 is a non-burning wrapper 18. Wrapper 18 is preferably a laminated
aluminum foil--paper structure. This wrapper minimizes or prevents
peripheral (radial) air from flowing to the portion of the fuel element
disposed longitudinally behind its forward edge, thereby causing oxygen
deprivation and preventing excessive combustion. A tipping paper 26 is
used to join the filter/tobacco cut filler segment to the front end
segment to form the cigarette.
The fuel elements employed herein should meet three criteria; (1) they
should be easy to ignite, (2) they should supply enough heat to produce
aerosol for about 5-15, preferably about 8-12 puffs; and (3) they should
not contribute off-taste or unpleasant aromas to the cigarette.
The preferred fuel element for use in the smoking articles of the present
invention is manufactured from a combustible material in such a way that
the density of the fuel element is greater than about 0.5 g/cc, frequently
about 0.7 g/cc or more, often about 1 g/cc or more, sometimes about 1.5
g/cc or more, but typically less than about 2 g/cc. Additionally, the fuel
element generally has a length, prior to burning, of less than about 20
mm, often less than about 15 mm, and preferably about 12 mm.
The composition of the combustible material of the fuel element can vary.
Preferred fuel elements contain carbon, and highly preferred fuel elements
are composed primarily of carbonaceous materials. Preferred carbonaceous
materials have a carbon content above about 60 weight percent, more
preferably above about 75 weight percent, and most preferably above about
85 weight percent. Flavors, tobacco, tobacco extracts, fillers (e.g. clays
or calcium carbonate), graphite, burn additives (e.g., sodium chloride to
improve smoldering and act as a glow retardant), combustion modifying
agents (e.g., potassium carbonate to control flammability), binders, and
the like, can be incorporated into the fuel element.
Surrounding the outer periphery of the fuel element is an improved
insulating member, which comprises one or more layers of wire cloth. An
especially preferred source of suitable wire cloth is Tetko Inc., 333 S.
Highland Avenue, Briarcliff, N.Y. 10510. The wire cloth useful herein as
an insulator may be manufactured from either metals or high temperature
stable synthetic materials. Suitable metals include aluminum, brass
(70/30), bronze, copper, nickel, stainless steel (302, 304, etc.), steel
and titanium, and the like. Suitable synthetic materials which are stable
when exposed to high temperatures (i.e., temperatures achieved by the fuel
elements used herein) will be readily apparent to the skilled artisan and
include Kevlar, Nomex, and the like.
The preferred wire cloth is a metal such as aluminum, and is available in
many combinations of wire diameters and mesh count. Mesh count is defined
as the number of openings in a lineal inch, measured from the center of
one wire to a point one inch distant. The mesh count preferably ranges
from about 50 to 400, most preferably from about 100 to 300. The diameter
of the wire can range from about 0.063 inches to about 0.0008 inches,
preferably from about 0.0005 inches to about 0.005 inches, and most
preferably from about 0.001 inches to about 0.003 inches.
The preferred metal wire cloth is also available several variations of
weave pattern, e.g., Plain Square Weave, Twilled Square Weave, Plain Dutch
Weave, Twilled Dutch Weave, Robusta Reverse Dutch Weave, Braided or Basket
Weave, and the like, each of which will afford different insulating
properties to the cigarette. Metal cloth having these weave patterns is
commercially available from G. Bopp & Co. of Zurich, Switzerland, and
their U.S. distributor, Tetko Inc, 333 Mount Highland Avenue, Briarcliff
Manor, N.Y. 10510, or Gerard Daniel Co., Inc., 5 Plain Avenue, New
Rochelle, N.Y. 10801.
The mesh size of the wire cloth can vary from about 2.times.2 to about
635.times.635. The open area of the wire cloth can vary considerably. For
instance, a 2.times.2 mesh wire cloth made with 0.063 inch diameter wire
has an open area of 76.4%. A 635.times.635 mesh wire cloth made with
0.0008 inch diameter wire has an open area of 25.8%. The degree (or
amount) of open area is an important factor in employing wire cloth as an
insulating means for cigarettes as described herein, because more open
area means more insulation power, whereas less open area means both less
insulation power and less oxygen admission to the fuel element. The larger
open areas also decrease the conductivity of the wire cloth. Preferably a
balance is achieved such that the fuel element receives sufficient oxygen
for burning, and the fuel element is adequately insulated to prevent
scorching or burning of materials which come into peripheral contact with
the cigarette. If desired, two or more different wire cloths, each
providing different open area may be combined, e.g., either in several
overlapping layers, or sequentially, i.e., in a manner which provides the
desired level(s) of insulating properties. These modifications may also
include texturizing or corrugating of the wire cloth to modify the open
area or degree of insulating power achieved by use of such materials.
For testing purposes, an aluminum wire cloth, having a plain square weave
was selected. This material was 200 mesh with 0.0021 inch diameter wire
with the open area of 33.6%. NOTE: this insulator does not necessarily
represent the optimization of the present invention. In fact, it is
believed that other modifications can be made in this insulator which will
show better performance characteristics. The test insulator however, did
serve to prove the utility of the presently claimed invention. In use,
this 200 mesh material served adequately as an insulator for an ignited
fuel element; i.e., there was no burning of paper placed in contact with
the periphery of the cigarette having this insulating means over the fuel
element. In addition, the fuel element performed normally, providing the
full number of desired puffs.
As described above, the aerosol generating means comprises a substrate
material and one or more aerosol forming materials. In the present
invention the substrate is a tobacco material, although other materials
are also suitable. The aerosol forming material may include a mixture of a
polyhydric alcohol such as glycerin and volatile flavoring agents such as
tobacco extracts, high fructose corn syrup, and the like. Examples of
other aerosol forming materials include volatile flavoring agents and
tobacco flavor modifiers. Volatile flavoring agents include vanillin,
cocoa, licorice, organic acids, high fructose corn syrup, and the like.
Various other flavoring agents for smoking articles are set forth in
Leffingwell et al., Tobacco Flavoring For Smoking Products (1972). Tobacco
flavor modifiers include levulinic acid, metal (e.g., sodium, potassium
calcium and magnesium) salts of levulinic acid, and the like.
As illustrated, the smoking articles of the present invention incorporate
one or more forms of tobacco. The form of the tobacco can vary, as can the
location or locations of the tobacco in the particular smoking article.
The tobacco can be incorporated in the fuel element, the aerosol
generating means, and/or positioned within the mouthend piece in a manner
so that various flavorful tobacco components are transferred to drawn
aerosol passing through the mouthend piece. The type of tobacco can vary,
and includes flue-cured, Burley, Maryland and Oriental tobaccos, and/or
known rare and specialty tobaccos, as well as blends of any thereof.
The extreme mouthend of the smoking article preferably includes a filter
element, or filter tip, particularly for aesthetic reasons. Preferred
filter elements are low efficiency filter elements which do not interfere
appreciably with aerosol yields. Suitable filter materials include low
efficiency cellulose acetate or polypropylene tow, baffled or hollow
molded polypropylene materials, or gathered webs or nonwoven polypropylene
materials.
The entire length of the smoking article, or any portion thereof, can be
overwrapped with paper. Preferred papers which circumscribe the front end
of the smoking article having the insulated fuel element and sleeve
assembly, should not openly flame during use of the smoking article,
should have controllable smolder properties, and should produce a gray
ash. Suitable papers are well known in the art.
Smoking articles of the present invention are capable of providing at least
about 6 to about 10 puffs, when smoked under FTC smoking conditions. FTC
smoking conditions consist of a 35 ml puff volume of 2 seconds duration,
separated by 58 seconds of smolder. Preferred smoking articles of the
present invention are capable of yielding at least about 0.6 mg of
aerosol, measured as wet total particulate matter (WTPM), in the first 3
puffs, when smoked under FTC smoking conditions. Moreover, preferred
smoking articles yield an average of at least about 0.2 mg of WTPM per
puff, for at least about 6 puffs, preferably at least about 10 puffs, when
smoked under FTC smoking conditions. Highly preferred smoking articles
yield at least about 5 mg of WTPM over at least 10 puffs, when smoked
under FTC smoking conditions.
The following example is provided in order to further illustrate the
preferred embodiment of the present invention, but should not be construed
as limiting the scope thereof. Unless otherwise noted, all parts and
percentages are by weight.
EXAMPLE 1
CIGARETTE OF FIG. 1
HEAT SOURCE SECTION (1):
The overall length of the entire Heat Source Section is 12 mm. The diameter
of this section is 7.5 mm (i.e., the diameter of a cigarette). The
component parts of the heat source section include the carbon fuel
element, the insulating means, and a paper overwrap which connects the
heat source section to the remainder of the cigarette.
Carbon Fuel Element
The carbon fuel element has a length of 12 mm and a diameter of 4.2 mm. The
fuel element composition is: 10 wt. % ammonium alginate binder; 5 wt. %
ball-milled tobacco powder; 1 wt. % sodium carbonate; 6 wt. % calcium
carbonate; 78 wt. % powdered hardwood carbon (average particle size 12
micron; prepared in an inert atmosphere). The fuel element is formed by
extrusion and has five equally spaced peripheral slots (15), each having a
depth of 1 mm and a width of 0.5 mm in the outer surface (i.e., the
periphery).
The hardwood pulp carbon is prepared by carbonizing a non-talc containing
grade of Grande Prairie Canadian kraft hardwood paper in an inert
atmosphere, increasing the temperature in a step-wise manner sufficient to
minimize oxidation of the paper, to a final carbonizing temperature of at
least 750.degree. C. The resulting carbon material is cooled in the inert
atmosphere to less than 35.degree. C., and ground to fine power having an
average particle size (as determined using a Microtrac Analyzer, Leeds &
Northrup) of about 12 .mu.m in diameter.
Insulating Means
Surrounding the outer periphery of the fuel element is the improved
insulating member, which comprises wire cloth which is commercially
available from Tetko Inc., 333 S. Highland Avenue, Briarcliff, N.Y. 10510.
The wire cloth is an aluminum wire cloth having a plain square weave. The
material is 200 mesh consisting of 0.0021 inch diameter wire, with an open
area of 33.6%. A piece of this material, about 12 mm.times.120 mm and
weighing about 0.15 g is wrapped or rolled around the fuel element in
several layers to provide a final outer diameter of about 7.5 mm. The wire
cloth covers only the fuel element, i.e., the final length of the
insulator is about 12 mm.
RECONSTITUTED TOBACCO SUBSTRATE (3):
The substrate is a reconstituted tobacco substrate in cut filler form, with
a length of 31 mm and a diameter of 7.5 mm. The reconstituted tobacco cast
sheet material is provided with high levels of glycerin as the aerosol
former. The base sheet composition is: 65 wt. % glycerin; 26 wt. %
extracted tobacco powder; 5 wt. % ammonium alginate; 4 wt. % DAP
(diammonium phosphate). On a percentage dry wt. basis, the substrate
material has an approximately 10-12% moisture content. The sheet is also
top loaded with -16 mesh size tobacco particles. The finished sheet is
then 80% base sheet and 20% top load by weight. The target moisture of the
finalized product is 6-7%.
The substrate is overwrapped with a 31 mm long paper--aluminum foil
laminate having a width of about 25.5 mm to form a substrate rod. The foil
in the laminate is cast aluminum, 0.0005 inches thick, and the paper is a
Simpson Paper Company product known as R JR LAM-5002 paper. The laminate
overwrap is formed with a commercial adhesive, Airflex 465 or silicate
adhesive.
RECONSTITUTED TOBACCO ROLL (5):
Following the substrate, there is another segment of tobacco, having a
length of about 30 mm and a diameter of about 7.5 mm. This segment is a
reconstituted tobacco sheet, in cut filler form, comprising the following
ingredients (on a dry weight basis); 95.4% reconstituted tobacco; 3.6%
glycerin; and 1.0% potassium carbonate. The moisture content of this cut
filler is about 13.5%. The reconstituted tobacco material is prepared in
cut filler form and is treated with a 6% casing (comprising 60%
glycerin/water solution and potassium carbonate).
FILTER ROD (7)
The filter rod has a length of about 10 mm and a diameter of about 7.5 mm.
The preferred material for this filter rod is cellulose acetate tow which
is commercially available from numerous sources. A cellulose acetate
filter rod about 7.5 mm diameter is formed from a 10/35,000 Denier tow
width 0.6% triacetin overwrapped with a 25.5 mm wide web of 646 plug wrap
available from Kimberly-Clark or Ecusta on a standard filter rodmaker. The
overwrapped rod is cut into 20 mm length segments.
PAPER OVERWRAP:
A paper--aluminum foil--paper laminate overwraps 4 mm of the mouthend side
of the heat source section 1 and all of substrate 3. The foil layer is not
porous, so there is no air flow through the laminate along either the heat
source section 1 or substrate section 3.
This front end overwrap tipping paper is advantageously formed by
laminating several papers including; an outer layer of Ecusta 29492 paper,
an intermediate layer of 0.0005 inch thick aluminum foil and an inner
layer of Ecusta 29492 paper. The laminated layers are held together with
an adhesive, LAM-5002, from R. J. Reynolds Tobacco Co., using 1.5 pounds
of adhesive per ream of paper.
The mouthend piece assembly and the front end piece assembly are aligned so
that the substrate abuts the tobacco paper plug and these sections are
secured together by a tipping paper about 45 mm in length to form a
cigarette.
The cigarette is smoked, and yields visible aerosol and tobacco flavor
(i.e., volatilized tobacco components) on all puffs for about 10-12 puffs.
The fuel element burns to about 6 mm back, i.e., to about the region where
the foil lined tube overwraps the fuel element, and there the cigarette
self-extinguishes. After the fuel element had been ignited, the cigarette
of FIG. 1 was placed upon a flat piece of paper, which neither scorched
nor ignited due to the insulating properties of the wire cloth insulating
means.
The present invention has been described in detail, including the preferred
embodiments thereof. However, it will be appreciated that those skilled in
the art, upon consideration of the present disclosure, may make
modifications and/or improvements on this invention and still be within
the scope and spirit of this invention as set forth in the following
claims.
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